Of rocky empires and solid marriages

William Dalrymple tells us that he was driven to write this book when, on a visit to Hyderabad in south India in February 1997, he learnt of the conversion to Islam in 1800 of James Achilles Kirkpatrick and of his marriage to Khair un-Nissa, a highly placed young aristocrat at the Nizam's court. This was the more remarkable because Kirkpatrick was at the time the East India Company's ambassador to Hyderabad, and that state played a pivotal role in the contest for south India then being waged between the company, Tipu Sultan's Mysore, the Marathas and Hyderabad itself. Moreover, as Dalrymple began his research, he discovered that there was hardly any mention of Kirkpatrick's domestic arrangements in English published sources, either contemporaneously or later; and that as he trawled through the archives there appeared to be more than a whiff of scandal and secrecy about the affair. He decided to investigate further.

Dalrymple found the chase exacting and exciting as he worked through archival files and tried to relate things to what he knew about Hyderabad on the ground. He establishes to his own satisfaction that Kirkpatrick and Khair un-Nissa were, so far as the elite of Hyderabad was concerned, a formally contracted couple, and he uses the evidence of Kirkpatrick's building at his residency, where provision was made for his wife and family, to show that this was recognised locally. He makes a good case for there being real love and a strong sexual attraction between the couple, but he finds some evidence to suggest that there were, at least from the Hyderabad side, political motives for the alliance. Moreover, he reveals that Kirkpatrick was reluctant to be open about his wife to his British friends, even to his brother.

In the course of writing about Kirkpatrick, Dalrymple touches on a good many other themes. He discusses other high-profile Indo-British marriages - there was a surprising number; he gives us a glimpse of British social life in India; he goes into the politics of the period, giving a more rounded Indian perspective than comes from standard accounts; and he follows the line of Kirkpatrick and his friends that Richard Wellesley's aggressive policy towards Mysore, Hyderabad, and the Marathas was morally unjustified and politically counter-productive to British interests.

It is an established historical method to take what, on the face of it, is a small subject in order to tell a big story and thus to subject the past to new analysis. Eamon Duffy did this in Voices of Morebath , where a parish tale is used to create a Reformation epic that challenges us to rethink life in 16th-century England. Perhaps it could have been done in this case, but Dalrymple has opted for a wider and more popular readership and he is less demanding of it than Duffy. Although his book is engagingly written and beautifully produced, it is indiscriminating in its scope and breadth - as much a high-class travelogue, with descriptions of cities and architecture and of social customs, as a work of history. And, since Dalrymple thinks that most of his readers will not know very much about India, he feels the need to give a lot of background. But instead of doing this by concise synthesis, he floods the reader with information, gazeteer-style, ranging from the early 16th century to the very end of the 19th. Still, White Mughals exudes pleasure and enthusiasm, and is deservedly a bestseller.

Towards the end of the book, Dalrymple returns to one of his major concerns - the value of cross-cultural explorations and the importance of tolerance and decency in human relations. His thin treatment of this key theme is somewhat at odds with the richness of much of his earlier narrative. He simply hopes that the easy cultural exchanges of the late 18th century hold out a beacon of hope for our own multicultural times. Kirkpatrick and his colleagues partook fully of the society and culture around them: what a fine example for our century.

But the story has its dark side also. Kirkpatrick died in 1805 and his children were sent to England to be brought up as wholly English. His son Mir Ghulam Ali became William George, and his daughter Noor un-Nissa became Katherine Aurora, or simply Kitty. As they grew up, they knew little of their distinguished Indian ancestry. Their mother, though not without continuing wealth and status, suffered the loss of her children, exile and social ostracism. Similar changes beset other Anglo-Indian families when interracial marriages fell from favour.

As the British became more dominant in India they became more aloof and distanced themselves from the enjoyment of Indian society. So they did not quite become white mughals, settling and mixing and ruling from within; rather, they took on the worst characteristics of Indian casteism and combined with them the worst snobberies of English class.

Soon after the Kirkpatrick children boarded ship for England, the young Lord Bentinck, then governor of Madras, reflected on the way the English in India were removed from Indian society: "We do not, we cannot, associate with the natives. We cannot see them in their houses and with their families... we are in fact strangers in the land." British rule as a consequence would be culturally less enriched and enriching than its predecessors, and, in the event, more transitory and uneven in impact than might otherwise have been the case.

Gordon Johnson is president, Wolfson College, Cambridge, and general editor of the New Cambridge History of India .